JPH01269865A - Refrigerating device - Google Patents

Abstract

PURPOSE:To maintain the inlet side pressure of a solenoid valve at more than or equal to the outlet side pressure in an excessive compression operating condition to prevent flow therein by providing a check valve at the connecting pipe part of the electromagnetic valve and a compressing chamber. CONSTITUTION:A basic refrigerating cycle is formed by a compressing chamber 1, a condenser 2 and an evaporator 3. When the compressor 2 is in an overheat condition, a thermostat 7 detects the temperature to turn on a solenoid valve 6, part of refrigerant liquefied by the condenser 2 is introduced in a compressing chamber in the process of compression through a connecting pipe 5, the solenoid valve 6 and a check valve 8 and the compressor is cooled by heat of evaporation of liquid refrigerant. When the compressor attains less than or equal to the fixed temperature, the thermostat 7 detects the temperature to turn off the solenoid valve 6 and liquid injection is completed. Further the check valve 8 is operated to prevent reverse flow in an excessive compressing operating condition at which the pressure of the check valve 8 part becomes high by the pressure of the condenser 2 part. As the result, the pressure 65 of the side of a piston upper face of the solenoid valve 6 can always be maintained at more than or equal to that 66 of the side of a piston lower face.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a refrigeration system, and more particularly to an overheat prevention device for a compressor.

[Conventional technology]

Regarding methods for preventing overheating of the secondary compressor, the injectilon cooling method is discussed in pages 162 to 165 of Hermetic Refrigerators published by the Japan Refrigeration Association (Yohei@Yoshi, 1981), and in page 285. A method of controlling the bypass amount of liquid refrigerant by opening and closing a solenoid valve is discussed on page 1. The conventional injector cooling method using a magnetic valve control cape is
Shown in Figure 4z. That is, the temperature of the compressor 1 or the discharge gas temperature is detected by the thermostat 7, and the solenoid valve 6 is opened and closed, and the injector W/il of the refrigerant liquefied in the condenser 2 is injected into the injector W/il.
A method of controlling was used.

[Problem to be solved by the invention]

In the above conventional technology, the compressor that forms the refrigeration cycle has a set capacity! In the case of the iIL type compressor, the relationship between the pressure P in the compression chamber into which the liquid refrigerant is introduced and the crank angle θ is as shown in FIG. The vertical axis is the compression chamber pressure P, and the horizontal axis is the crank angle θ. Symbols P8 and P2 indicate the pressure at the start and end of liquid injection, respectively, and the pressure P in the compression chamber into which the liquid refrigerant is introduced changes from Pl to P during the compression stroke.
A pulsating flow that changes up to 2 is formed.

However, in the case of a cooling operation in the winter when the outside air temperature is low, the condenser side pressure P3 becomes lower than the liquid injector pressure P2, resulting in an overcompression operation. 1 during this overcompression operation.
The table shown in Figure g4 shows the piston F side pressure 66, which is in communication with the pressure P1 during the injection stroke, and the condenser side pressure P.
, and the pressure on the upper surface of the piston 65, which is in communication with the piston, is continuously reversed, so the piston 64 starts to vibrate up and down, which significantly wears out the pilot valve 68 and the seat surface of the piston 64. This caused a problem in that it shortened the life of the solenoid valve.

An object of the present invention is to enable the artificial side pressure of the solenoid valve to be maintained above the outlet side pressure even in an overcompression operating state, and to prevent backflow within the solenoid valve.

[Means for resolving charges]

The above object is achieved by providing a check valve in the connecting pipe section through which the refrigerant liquefied in the condenser is introduced into the compression chamber during the compression stroke.

[Effect]

During over-compression operation, the check valve closes when the pressure on the inlet side becomes higher than the condensing pressure, so the pressure on the solenoid valve's manifold side can always be maintained above the outlet side pressure, which prevents backflow from occurring within the solenoid valve. Since there is no such thing, the solenoid valve will not malfunction.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a refrigeration cycle according to the present invention, in which a basic refrigeration tickle is constituted by a compressor 1, a condenser 2, an expansion valve 8, and evaporative beneficial insects. A part of the refrigerant liquefied by the condensation 5z passes through the connecting pipe 5, the electromagnetic valve 6, and the check valve 8, and is introduced into the compression chamber during the compression stroke. Furthermore, a thermostat 7 is attached to the royal machine to control the opening and closing of the solenoid valve 6.

Next, the effect will be explained.

compression! ! 2 is in an overheated state, the thermostat 7 detects the temperature and turns on the solenoid valve 6, and a part of the refrigerant liquefied by the condenser 2 is introduced into the compression chamber during the compression stroke, and the heat of evaporation of the liquid refrigerant The compressor is cooled. Pressure #! When the temperature falls below a predetermined value, the thermostat 7 sharply increases the temperature, turns off the solenoid valve 6, and ends the liquid injection.

In an overcompression operating state in which the pressure in the check valve 8 section is higher than the pressure in the condenser 2 section, the check valve 8 operates to prevent backflow.

As a result, the piston/upper surface pressure 65 of the solenoid valve 6 shown in FIG. 4 can always be maintained at or above the piston lower surface pressure 66.

According to this embodiment, since the vertical vibration of the piston 64 shown in FIG. 4 can be prevented, the pilot valve 68 and the piston 64
It is possible to eliminate abnormal noise caused by the collision of the sheet tH with the seat tH.

〔Effect of the invention〕

According to the present invention, it is possible to prevent backflow of the solenoid valve even in an overcompression operation state that occurs when using a set displacement compressor, thereby preventing a decrease in the life of the solenoid valve and improving the reliability of the refrigeration cycle. .

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram of an embodiment of the present invention, Fig. 2 is a conventional refrigeration cycle diagram, Fig. 8 is a diagram showing the relationship between beam 7Fy angle and pressure in the compression chamber, and Fig. 4 is a diagram of a conventional refrigeration cycle. FIG. 3 is a sectional view showing the structure of the solenoid valve shown in the figure. 1... Compressor 2... Condensing giSs... Expansion valve 4... Evaporation 55... Connecting pipe 6... Solenoid valve
7... Thermostat 8... Check valve. One group of brooms, one pressure insect sacrifice. 10th 31 Figure 4

Claims (1)

[Claims] 1. Consists of a connecting pipe that introduces a part of the refrigerant liquefied in the condenser of the refrigeration cycle into the compression chamber during the compression stroke, and a solenoid valve that controls the injection amount of the liquid refrigerant. A refrigeration system characterized in that, in a compressor overheat prevention device, a check valve is provided in a connecting pipe section between the electromagnetic valve and the compression chamber. 2. Claim 1, characterized in that a set displacement compressor is provided as the compressor constituting the refrigeration cycle.
Refrigeration equipment as described in section.